This Korean instant soup is a quick stovetop bowl of kimchi, soft tofu, mushrooms, and zucchini in a savory, gently spicy broth. It takes its cues from Korean kimchi stews and soups, with an easy vegetable-stock base that makes a warming meal without a long simmer.
Ingredients
- 1 tablespoon (15 ml) toasted sesame oil
- 2 cloves garlic, minced (about 2 teaspoons or 6 g)
- 1 teaspoon (2 g) gochugaru, Korean red pepper flakes, plus more to taste
- ½ cup (75 g) chopped well-fermented kimchi, plus 1 tablespoon (15 ml) kimchi juice
- 1 cup (100 g) sliced shiitake or cremini mushrooms
- 1 cup (130 g) diced zucchini, cut into roughly ½-inch (1 cm) pieces
- 1 tablespoon (18 g) doenjang, Korean fermented soybean paste
- 6 cups (1.4 L) low-sodium vegetable stock
- 1 tablespoon (15 ml) Korean soup soy sauce, called gukganjang
- 1 teaspoon (5 ml) gochujang, Korean fermented chili paste
- 14 ounces (397 g) soft or medium tofu, cut into 1-inch (2.5 cm) pieces
- 2 scallions, thinly sliced (about ¼ cup or 25 g)
- 1 teaspoon (5 ml) rice vinegar, or to taste
- ¼ teaspoon fine salt (about 1.5 g), plus more only if needed
- 1 teaspoon (3 g) toasted sesame seeds, optional, for serving
Instructions
- Prepare the vegetables and tofu before heating the pot: mince the garlic, slice the mushrooms and scallions, dice the zucchini, and cut the tofu into large pieces. Drain the tofu only if the package contains a lot of packing liquid; soft tofu is delicate, so handle it gently. Keep the kimchi juice, since it adds acidity and seasoning to the broth.
- Set a medium Dutch oven or heavy soup pot over medium heat. Add the sesame oil, garlic, and gochugaru. Stir for about 30 seconds, just until fragrant. Do not let the garlic brown or the pepper flakes scorch; either can make the finished soup taste bitter.
- Add the kimchi and its juice, mushrooms, and zucchini. Stir for 2 minutes so the vegetables are coated in the seasoned oil and the kimchi begins to smell fragrant. Stir in the doenjang and gochujang, pressing them against the side of the pot to loosen them and spread their flavor through the vegetables.
- Pour in the vegetable stock and add the soup soy sauce. Bring the liquid to a gentle boil, then reduce the heat and simmer uncovered for 10 minutes. Keep the soup at a steady simmer rather than a hard boil; that gives the zucchini time to soften while leaving the mushrooms with some texture. Taste a spoonful of broth near the end of the simmer.
- Gently slide in the tofu and simmer for 3 minutes, taking care not to break it up as you stir. Add the sliced scallions and rice vinegar. Taste again, then add the salt if needed. For a hotter broth, stir in another pinch of gochugaru; for a saltier, more rounded broth, add a little more gukganjang. Ladle into bowls while hot, adding sesame seeds if desired.
Tips
- Choose kimchi with the right flavor. Well-fermented kimchi gives this soup a deeper, tangier broth than very fresh kimchi. If yours is mild or newly opened, add the rice vinegar gradually and taste before adding extra; kimchi brands and fermentation levels vary. For a vegetarian version, check that the kimchi contains no fish sauce or shrimp paste, and choose vegetable stock that is not heavily salted.
- Adjust the heat in small steps. Gochugaru gives the broth a clean, warm chili flavor, while gochujang adds fermented sweetness and body. Start with the listed amounts, then add more after simmering. If you cannot find gochugaru, use a small pinch of crushed red pepper flakes; the soup will still be spicy, but the chili flavor will be less rounded and less distinctly Korean.
- Use a measured hand with substitutes. Gukganjang has a lighter color and a more pronounced savory flavor than regular soy sauce. If it is unavailable, use 1 tablespoon (15 ml) low-sodium soy sauce and season with salt only after tasting; regular soy sauce can darken and salt the broth more. If doenjang is hard to find, use 1 tablespoon (15 g) white or yellow miso instead. Miso is usually milder and sweeter, so the broth will have less earthy fermented depth.
- Keep the tofu intact. Soft tofu makes a tender, spoonable soup, but it can crumble if stirred vigorously. Cut it into generous pieces and fold it in near the end. Medium tofu is easier to handle and still tender; firm tofu works too, though the soup will have a chewier texture rather than the soft, custardy feel associated with sundubu-style bowls.
Serving Suggestions
Serve the soup in warm bowls as soon as the tofu is heated through. Steamed short-grain rice is the classic, practical partner: serve it in a separate bowl, or spoon the soup over rice for a more filling one-bowl meal. If serving rice, cook it separately while preparing the soup; rice-cooking time is not included in the recipe timing.
A few simple sides make a balanced table without competing with the spicy, tangy broth. Try cucumber dressed with rice vinegar and a little sesame oil, blanched spinach seasoned with sesame, or store-bought kimchi if you would like more crunch and acidity. Set extra sliced scallions, sesame seeds, and gochugaru on the table so everyone can adjust their own bowl. The broth is flavorful, so plain rice and lightly seasoned vegetables are especially good accompaniments.
Variations
For a more substantial soup, add 1 cup (150 g) sliced napa cabbage or a handful of enoki mushrooms along with the zucchini. If you add more vegetables, the broth will be less concentrated; add up to ½ cup (120 ml) extra stock if the pot becomes crowded, then taste and adjust the seasoning. For a simple noodle version, add cooked noodles to individual bowls and ladle the soup over them. Keep noodles separate until serving so they do not absorb the broth and turn soft in the pot.
To make the soup less spicy, reduce the gochugaru to ½ teaspoon (1 g) and omit the gochujang. It will still be savory and tangy, although less robustly chili-forward. For a richer, nonvegetarian variation, use chicken stock in place of vegetable stock; this changes the soup’s flavor but keeps the quick method the same. You can also replace zucchini with thinly sliced onion or extra mushrooms. Korean soups and stews have many household and regional variations, so these changes are practical adaptations rather than a claim that there is only one fixed version.
Storage and Reheating
Let leftover soup cool briefly, then refrigerate it within 2 hours of cooking in a covered, shallow container. It keeps for 3 to 4 days in the refrigerator. The tofu may become a little firmer and the kimchi flavor more pronounced as it sits; that is normal. Store rice separately if you made it, and avoid leaving the soup at room temperature for an extended period.
Reheat only the portion you plan to eat in a saucepan over medium heat, stirring gently until steaming hot throughout. Add a splash of water or stock if the broth has reduced or tastes too concentrated. For food safety, USDA FSIS recommends reheating leftovers to 165°F (74°C); check the center with a food thermometer if you need to verify the temperature. A microwave also works: use a microwave-safe bowl, cover loosely, heat in short intervals, and stir carefully between intervals so the soup warms evenly without breaking up all the tofu. Freezing is possible for up to 2 months, but soft tofu can turn grainy after thawing, so the texture is best when the soup is refrigerated and eaten within a few days.
Frequently Asked Questions
Is this Korean instant soup made from a packet?
This recipe is made from scratch in one pot rather than from an instant soup packet. The word instant describes its quick preparation: the soup is ready in about 30 minutes, using ingredients such as kimchi, tofu, stock, and Korean seasonings. Packaged Korean soups vary in salt and spice, so follow their package directions if using one instead.
How spicy is the soup?
At the listed quantities, it has a noticeable but moderate chili warmth. Kimchi, gochugaru, and gochujang vary in heat, so your bowl may be milder or hotter depending on the products you use. Reduce the gochugaru and omit the gochujang for a gentler version, or serve extra pepper flakes at the table for people who want more heat.
Can I make it without doenjang?
Yes. Doenjang adds a salty, earthy fermented flavor, but the soup will still work without it. White or yellow miso is the closest easy substitute; use the same amount, then taste before adding salt because miso can be salty. If you leave it out entirely, the broth will taste lighter, so a small extra splash of gukganjang may help.
What kind of tofu is best?
Soft or medium tofu gives the soup a tender texture, and soft tofu is the closest choice for a sundubu-inspired bowl. Medium tofu is easier to portion and stir without breaking. Firm tofu is a good option if that is what you have, but it makes the soup more substantial and less delicate. Add any type near the end so it warms without falling apart.
Can I make the soup ahead?
Yes. You can make it up to 3 days ahead and refrigerate it promptly, though the tofu may firm up and the broth may become more tangy. Reheat it gently with a splash of stock or water, and add fresh scallions just before serving for a brighter finish. For the best texture, cook the soup without tofu, refrigerate the broth and vegetables, then add tofu while reheating and simmer until hot.
What can I use instead of vegetable stock?
Water works, but the broth will be less full-bodied; add a little extra doenjang or gukganjang only after tasting. Low-sodium chicken stock is another option if you are not keeping the dish vegetarian. Avoid strongly seasoned or very salty stock, since kimchi, fermented pastes, and soup soy sauce already contribute plenty of savory flavor.
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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
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